So far, there has been the so-called real image type view finder known for camera's finders, in which a real image is formed through an objective optical system so that the real image is viewed through an eyepiece optical system. The real image type view finder known so far in the art, for instance, includes a finder wherein an image formed on a screen mat through a taking optical system in the form of an objective optical system is viewed through a penta roof prism and an eyepiece optical system, and a finder that is optically independent from a taking optical system.
The former finder, because of the need for space for receiving the penta roof prism, works against size reduction of the taking apparatus. The latter gives rise to parallaxes between the image being taken and the image being view upon close-range shooting, because the optical axis of the taking optical system is separate away from the optical axis of a finder's objective lens. This is also unsuitable for checking an in-focus state using the taking optical system.
With recent improvements in the performance of electronic display devices, an electronic view finder designed to use an eyepiece optical system to view an image displayed on the display surface of an electronic display device is going mainstream in the digital camera or video camera field.
A typical electronic view finder receives signals from an image formed on an imaging device through a taking optical system to display the subject's image to be viewed. Thus, there is no parallax between the image being taken and the image being viewed, and the ability to have a grasp of whether the image being taking is in focus or not is achievable. In addition, the distance from the display surface of the electronic image device to an exit pupil can be curtailed, offering a sensible tradeoff between making sure the field of view of the image being viewed and size reduction.
Referring to the thickness of the display device used on the electronic view finder, on the other hand, it has some influences on the optical axis size of the finder when the optical axis of the display device extends straight. JP(A)'s 2009-282181 and 2005-84284 disclose an electronic view finder wherein a reflective surface is inserted in an optical path through it to make the finder short in its lengthwise direction.